Teaching global warming to today’s generation of students is not that simple. Apart from the raging debate on the internet about the truth behind global warming and climate change that is confusing students, the inquisitive nature of Gen Z kids makes it difficult for teachers to explain the topic without giving valid proof.
So is global warming true? Of course it is, and no essays or research papers on global warming can validate our claim without scientific proof. The good thing is that global warming can be proved through a simple experiment that can be performed in a classroom! Before we start with the experiment, let’s quickly brush up on what global warming and greenhouse effect means.
Greenhouse gases like carbon dioxide, methane, nitrous oxide, etc., form a layer around the earth’s atmosphere that traps the heat from sun’s infrared rays and thus heats the earth’s surface. This phenomenon is called greenhouse effect and it has a huge role to play in global warming. In simple words, global warming is an increase in the earth’s temperature due to a steep rise in the level of carbon dioxide as a result of human activities like burning of fossil fuel, deforestation, etc.
Since we have stated that carbon dioxide causes global warming, it is time to prove our claim right by conducting an interesting experiment called ‘Global Warming in a bottle’. Here are the things that you would need to conduct the experiment in the classroom:
Two empty transparent soda bottles
Baking Soda
Vinegar
Two glass thermometer
A study lamp
Scotch tape/ Rubber stopper
Once you have collected all the materials needed for the experiment, follow the steps given below:
Take two empty transparent soda bottles and fill them half with water.
In one of the bottles, add a little vinegar and baking soda. Vinegar reacts with baking soda to produce carbon dioxide.
Close the mouth of two bottles by using a scotch tape or laboratory rubber stoppers.
Stick two glass thermometers through the tape/stoppers to measure the temperature of both the bottles respectively.
Switch on the study lamp and place it near the bottles in such a way that light from the lamp falls directly on the surface of the bottle. Here, lamp acts as a heating source.
After 40-45 mins, check the temperature of both the bottles.
Expected Result of the experiment:
The temperature in the bottle containing carbon dioxide should be relatively higher as compared to the other bottle. This would prove that carbon dioxide plays a major role in the rise of temperature.
Q & A
Once you have intrigued your students with this experiment, here are a few questions that a teacher needs to discuss with students:
Q: How did baking soda and vinegar form carbon dioxide?
A: As mentioned before, the chemical reaction between vinegar and baking soda produces carbon dioxide. Vinegar, also known as acetic acid has chemical formula of C2H4O2. And baking Soda, which is sodium bicarbonate, has chemical formula of NaHCO3. Here’s their chemical reaction to produce carbon dioxide and water.
C2H4O2. + NaHCO3 ---------------> NaC2H3O2 + H2O + CO2
Q:Why does carbon dioxide cause global warming?
A: The lamp sends infrared rays which penetrates the surface of the bottle, but when these heat waves try to escape from the surface of the bottle, carbon dioxide, which is a greenhouse gas, traps the infrared rays. Thus, the temperature inside the bottle rises and it leads to global warming.
Q:How do humans contribute to global warming?
A: Everything from industrialisation to deforestation to burning of fossil fuels release harmful gases in the atmosphere, including carbon dioxide, that forms a strong greenhouse gas layer around the earth’s atmosphere, which in turn increases the temperature and causes global warming. In fact, something as essential and seemingly harmless like agricultural activities can contribute to global warming. In order to produce high yields of crops while tackling unpredictable weather conditions, there has been an increased use of fertilizers and pesticides that release greenhouse gases like carbon dioxide, nitrous oxide, etc., in the atmosphere. Farming industries are highly dependent on tractors and other equipments that run on fuel, again contributing to increasing levels of greenhouse gases.
Q: What can be done to curb global warming?
A: While the simple answer to this question would be to limit the expulsion of greenhouse gases, it is easier said than done. Planting trees, saving forests, planned industrialisation, using public transportation and organic farming are a few ways to arrest the rate of global warming. By adopting green farming or organic farming, we can use natural fertilizers like compost, green manure, etc., that are organic and don’t contribute to the emission of greenhouse gases. Techniques like crop rotation and companion planting helps in increasing soil nutrients that will lead to an increase in crop yield. Organic farming is growing in popularity and might be the road forward to tackle global warming.
Additional activities:
1. If possible, take students on a tour to an organic farm where they would learn about techniques of green farming without using fertilizers and pesticides that harm the environment.
2. Introduce the concept of carbon footprint in the classroom so that students can see how their day to day activities are contributing to global warming. Ask students to figure out ways to lower their carbon footprint.
Hope this experiment helps you in explaining the threat of global warming to your students.
